1) Field of the Invention
The invention herein relates to a multipurpose drilling jig having applications as a woodworking tool that assists in drilling series of perpendicular holes.
2) Description of the Prior Art
When drilling holes in woodworking, the best quality is achieved by utilizing a specialized vise or clamps to assist the operation. This is especially true in the case of most do-it-yourself household furniture. One common example is the perpendicular conjoinment of the two wood planks A and B, as indicated in FIG. 2, FIG. 3, and FIG. 4, wherein a series of holes must be drilled for the perpendicular insertion of the dowels C to accomplish the conjoinment. When drilling holes in woodworking, the best quality is achieved by utilizing a specialized vise or clamps to assist the operation. This is especially true in the case of most do-it-yourself household furniture. One common example is the perpendicular conjoinment of the two wood planks A and B, as indicated in FIG. 2, FIG. 3, and FIG. 4. A series of holes must be drilled for the perpendicular insertion of the dowels C to accomplish the conjoinment. The holes in the two wood planks A and B must be drilled accurately such that they are equidistantly apart from one another. Any discrepancy will preclude serial conjoinment. A drilling jig is therefore used. As shown in FIG. 1, the drilling jig is composed of a jig body 1 and a perpendicular stop 2 at the bottom section of the jig body 1. Three locating holes 3 are bored in the top section 1a of the jig body 1 for the placement of a guide sleeve 4 and two locating pins 6a to guide the drilling of the holes. The provisions for attaching a handle 5 are provided at the rear end 1b, whereas the parallel straddling slots 6 and 7 are formed in the front end 1c and the perpendicular stop 2, so as to provide straddling over the woodworking dowels C. As shown in FIGS. 2-4, the perpendicular stop 2 is supported against the side of the wood planks and the guide sleeve 4 in the top section of the jig body 1, so as to drill the perpendicular holes. Thereafter, the dowels C are inserted into the holes already drilled and then into the front end 1c of the jig body 1 or the parallel straddling slots 6 and 7, which are straddled into position over the outer diameter of the perpendicular woodworking dowels C such that the perpendicular dowels C are in the plank A, and that the straddling slots 6 and 7 serve as a standard criterion for positioning the guide sleeve 4 in the top section of the jig body 1 to guide the drill bit in the boring of the perpendicular holes in other wood plank B, thereby completing the operation of drilling the holes needed to conjoin the two wood planks A and B. The conventional dowel hole drilling jig seems practical; nevertheless it is not confirmed in actuality. A variety of dowel diameters and physical dimensions are available. The width of the front end 1c of the jig body 1 and the width of the straddling slots 6 and 7 in the perpendicular stop 2 are fixed. If the straddling slot width of the drilling jig is not exactly the same as the diameter and the physical dimensions of the working dowels, the drilling jig will be unusable, thereby requiring additional purchase of another unit matching the specifications. In addition, the guide sleeve 4 in the top section of the jig body 1 inserted into the locating hole 3 is freely movable, it is readily dislodged and lost during utilization or carriage, especially at the time when the drill bit is raised and when the guide sleeve 4 falls out after being drawn up. This type of the jig can only be utilized as drilling jig on level surfaces and does not function fully for drilling a vertical woodworking object.
In view of the said shortcomings, the inventor of the invention herein, based on many years of experience in the production and marketing of this category of products, conducted extensive research and testing, which finally culminated in the development of the practical invention herein.